Methylglyoxal concentration and glyoxalase activities in the human lens.

The activities of glyoxalase I and glyoxalase II and the concentration of methylglyoxal were determined in 26 human lenses. The activity of glyoxalase I (mean +/- S.D.) was 15.62 +/- 3.90 U (g wet weight)-1 and the activity of glyoxalase II was 0.189 +/- 0.087 U (g wet weight)-1 (n = 26). The concentration of methylglyoxal of the human lenses was 1.78 +/- 0.84 nmol (g wet weight)-1 (n = 26). There was a significant negative correlation of both the activity of glyoxalase I and the activity of glyoxalase II with subject age but no correlation of methylglyoxal concentration with subject age. The concentration of methylglyoxal in the lenses was approximately 20-fold higher than in blood samples from normal human subjects. Given the previously reported decrease in the concentration of reduced glutathione in the human lens with age, there is expected to be a marked decrease in in situ activity of glyoxalase I and concomitant susceptibility of human lens proteins to modification by methylglyoxal with age. The metabolism of methylglyoxal and the formation of methylglyoxal-modified proteins may be linked to the development of senile and diabetic cataract.

The Weill-Marchesani syndrome: report of two cases and a review.

Two cases of the Weill-Marchesani syndrome are reported. The diagnosis very likely is being missed in some cases in which the skeletal abnormalities are minor and the patients are not referred for systemic examination. Medical therapy has not been successful in most patients for the management of the pupillary-block angle-closure glaucoma encountered in this syndrome. Laser iridectomy, which does not risk vitreous fluid loss and other serious surgical complications in this disorder, probably is a safer choice as an initial procedure than is the use of peripheral iridectomy. A review of the pathogenesis of the syndrome and of its treatment is included.

Update on the management of glaucoma.

Most cases of chronic open-angle glaucoma can be treated medically. When medical management is ineffective, laser trabeculoplasty is usually performed. If medical management and laser treatment fail, surgery is the next step. Recently, ultrasound has been employed successfully for control of glaucoma when medical, laser, and surgical treatments were not successful. Acute angle-closure glaucoma is an ophthalmic emergency. This condition can be treated at an early stage by relieving the pupillary block with peripheral iridectomy by laser or surgery. Four major classes of drugs are currently used to treat glaucoma: carbonic anhydrase inhibitors, beta adrenergic blockers, parasympathomimetics, and sympathomimetics. Both local and systemic side effects may occur secondary to glaucoma medications and some of these may be severe or even fatal. These adverse reactions are discussed.

Diabetic retinopathy: a leading cause of new blindness.

Some of the basic underlying processes in the development of diabetic retinopathy include changes in the walls of retinal vessels, with occlusion and leakage. These result in edema, hemorrhage, hard exudates, plaques, and ischemia, leading to neovascularization. When proliferative retinopathy supervenes, it may result in complete blindness. Internists and family practice physicians should be alert for early signs of diabetic retinopathy. Ideally, diabetic patients should have their eyes examined yearly by an ophthalmologist. A fundus examination without dilation and usually without acuity testing rarely detects proliferative or early background retinopathy. Multicenter studies have shown that photocoagulation of new vessels with the argon laser may significantly reduce the incidence of severe visual loss. This treatment method has the potential of reducing the incidence of diabetic blindness by 60% to 80%. Photocoagulation is not a "cure" for diabetic macular edema; when used judiciously, however, it can sometimes further reduce visual loss caused by this common disease. The course of diabetic retinopathy in individual cases is unpredictable. After photocoagulation, some patients cannot see as well as before, though in others the progress of the disease is arrested. There is a conservative concern about a procedure that destroys retinal tissue in the hope of limiting the progression of the disorder. Yet photocoagulation appears to be the only alternative until a better treatment is developed through basic research.

Management of pterygia: should thiotepa be used?

Pterygium, a common source of morbidity throughout the world, may appear to be an innocuous, easily excised lesion, yet it plagues the ophthalmologist by its high rate of recurrence, ranging from 20% to 30% after simple excision. Beta irradiation has been used by ophthalmic surgeons for many years. Another method of stemming the high percentage of pterygium recurrence is through local application of thiotepa, a radiomimetic drug that inhibits rapidly proliferating cells. The following report is a review of the literature from 1960 to 1977 on the role of thiotepa in treatment of pterygium, with emphasis on the complications of thiotepa administration. The recurrence rate after topical postoperative use of thiotepa ranges from 0 to 8%, with disturbing variance in results, depending on each investigator's definition of "recurrence", the length of follow-up, the type of pterygium, and the number of patients. The main reported complication from thiotepa's use has been depigmentation of skin around several patients' eyes, sometimes precipitated by exposure to the sun's rays.

Management of patients with glaucoma and cataract.

The recent rise in the number of patients with both glaucoma and cataracts has increased the controversy over the management of these concurrent problems. Visual acuity, strength of medication, and previous surgery must be considered when determining whether to do cataract extraction alone, glaucoma surgery alone, or a combined procedure. We have found that the type of glaucoma the patient has influences our choice of surgery. The combined procedure is reserved for patients who have had repeated attacks of angle-closure glaucoma and those whose open-angle glaucoma is difficult to control. Thermal sclerostomy with cataract extraction was successful in maintaining intraocular pressures of 18 mm Hg or lower without medication in 48 of 58 patients.